Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users
Stanley Sheft1, Min-Yu Cheng1, Valeriy Shafiro1
1Department of Communication Disorders and Sciences, Rush University Medical Center, Chicago, IL.
Journal of the American Academy of Audiology
|July 3, 2015
Summary
Cochlear implant (CI) users show deficits in discriminating low-rate frequency modulation (FM) patterns, impacting their speech perception in noise. This suggests a shared neural basis for processing temporal auditory information.
Area of Science:
- Auditory Neuroscience
- Speech Perception
- Signal Processing
Background:
- Low-rate frequency modulation (FM) aids speech intelligibility and signal coherence.
- Understanding FM processing is crucial for improving cochlear implant (CI) outcomes.
Purpose of the Study:
- To investigate if CI users' speech perception difficulties correlate with impaired discrimination of stochastic low-rate FM patterns.
- To assess the relationship between FM discrimination abilities and speech-in-noise perception in CI users.
Main Methods:
- Correlational study with 13 postlingually deafened adult CI users.
- Measured FM discrimination thresholds in quiet and noise, considering frequency excursion, duration, and signal-to-noise ratio.
- Assessed speech perception in noise using Pearson correlation and commonality analysis.
Main Results:
- CI users had higher mean FM discrimination thresholds than normal-hearing individuals.
- Masked speech intelligibility correlated significantly with FM discrimination metrics (signal-to-noise ratio, duration).
- Shared variance among FM discrimination measures explained a substantial portion of the speech perception effect.
Conclusions:
- Impaired processing of stochastic FM patterns may contribute to speech-in-noise deficits in CI users.
- Discrimination of temporally distributed place coding in stimuli could be a common basis for these deficits.
- This highlights a potential target for auditory rehabilitation strategies in CI users.
